Phase detecting device, phase control device including the phase detecting device, and fuser control device including the phase control device

Abstract

A phase detecting device includes a power input unit that receives an AC voltage; a phase detector that detects zero-crossing points of the AC voltage, and outputs a phase detecting signal when the zero-crossing points of the AC voltage are detected; and a power switch that selectively cuts off a flow of AC into the power input unit in response to a mode control signal.

1. A phase detecting device comprising:
 a power input unit that receives an AC voltage; 
 a phase detector that detects zero-crossing points of the AC voltage, and outputs a phase detecting signal when the zero-crossing points of the AC voltage are detected; and 
 a power switch that selectively cuts off a flow of AC power into the power input unit in response to a mode control signal; 
 wherein the phase detector does not detect the zero-crossing points of the AC voltage when the power switch cuts off the flow of the AC power into the power input unit in response to the mode control signal. 
 
   
   
     2. The phase detecting device of  claim 1 , wherein the power input unit comprises a full-wave rectifier that outputs a rectified AC voltage. 
   
   
     3. The phase detecting device of  claim 2 , wherein the phase detector detects the zero-crossing points of the AC voltage from the rectified AC voltage outputted from the full-wave rectifier. 
   
   
     4. A phase detecting device comprising:
 a power input unit that receives an AC voltage; 
 a phase detector that detects zero-crossing points of the AC voltage, and outputs a phase detecting signal when the zero-crossing points of the AC voltage are detected; and 
 a power switch that selectively cuts off a flow of AC power into the power input unit in response to a mode control signal; 
 wherein the mode control signal comprises:
 a standby mode control signal that controls the power switch to operate in a standby mode in which a power consumption of the power input unit is reduced by cutting off the flow of the AC power into the power input unit, and the phase detecting signal is not outputted from the phase detector; and 
 a normal mode control signal that controls the power switch to operate in a normal mode in which the AC power flows into the power input unit, and the phase detecting signal is outputted from the phase detector when the zero-crossing points of the AC voltage are detected. 
 
 
   
   
     5. The phase detecting device of  claim 4 , wherein the power switch comprises a first photocoupler. 
   
   
     6. The phase detecting device of  claim 5 , wherein the power switch further comprises a first 3-terminal element
 wherein the first 3-terminal element comprises:
 a first terminal that receives the mode control signal, 
 a second terminal that receives a predetermined DC voltage and is connected to the first photocoupler, and 
 a third terminal that receives a ground voltage; and 
 
 wherein the first 3-terminal element
 provides the first photocoupler with the ground voltage at the second terminal of the first 3-terminal element in response to the standby mode control signal, and 
 provides the first photocoupler with the predetermined DC voltage at the second terminal of the first 3-terminal element in response to the normal mode control signal. 
 
 
   
   
     7. The phase detecting device of  claim 6 , wherein the power input unit comprises:
 a resistor circuit that divides the AC voltage and outputs a divided AC voltage; and 
 a bridge rectifier that rectifies the divided AC voltage and outputs a rectified AC voltage; and 
 wherein the phase detector detects the zero-crossing points of the AC voltage from the rectified AC voltage outputted from the bridge rectifier. 
 
   
   
     8. The phase detecting device of  claim 7 , wherein the phase detector comprises a second photocoupler connected to the bridge rectifier of the power input unit and the first photocoupler of the power switch. 
   
   
     9. The phase detecting device of  claim 8 , wherein the phase detector further comprises a second 3-terminal element;
 wherein the second 3-terminal element comprises:
 a first terminal that receives the predetermined DC voltage and is connected to the second photocoupler, 
 a second terminal that receives the predetermined DC voltage; and 
 a third terminal that receives a ground voltage, and 
 
 wherein the second 3-terminal element
 outputs the ground voltage from the second terminal of the second 3-terminal element as the phase detecting signal when the zero-crossing points of the AC voltage are detected and the power switch is operating in the normal mode in response to the normal mode control signal, 
 outputs the predetermined DC voltage from the second terminal of the second 3-terminal element when the zero-crossing points of the AC voltage are not detected and the power switch is operating in the normal mode in response to the normal mode control signal, and 
 outputs the ground voltage from the second terminal of the second 3-terminal element when the power switch is operating in the standby mode in response to the standby mode control signal. 
 
 
   
   
     10. A phase detecting device comprising:
 a power input unit that receives an AC voltage; 
 a phase detector that detects zero-crossing points of the AC voltage, and outputs a phase detecting signal when the zero-crossing points of the AC voltage are detected; and 
 a power switch that selectively cuts off a flow of AC power into the power input unit in accordance with whether the power switch is operating in a normal mode or a standby mode; 
 wherein the power switch cuts off the flow of the AC power into the power input unit when the power switch is operating in the standby mode; and 
 wherein the phase detector does not detect the zero-crossing points of the AC voltage when the power switch cuts off the flow of the AC power into the power input unit when the power switch is operating in the standby mode. 
 
   
   
     11. A phase detecting device comprising:
 a power input unit that receives an AC voltage; 
 a phase detector that detects zero-crossing points of the AC voltage, and outputs a phase detecting signal when the zero-crossing points of the AC voltage are detected; and 
 a power switch that selectively cuts off a flow of AC power into the power input unit in accordance with whether the power switch is operating in a normal mode or a standby mode; 
 wherein the standby mode is a mode in which the power switch cuts off the flow of the AC power into to the power input unit to reduce a power consumption of the power input unit, and the phase detecting signal is not outputted from the phase detector; and 
 wherein the normal mode is a mode in which the power switch allows the AC power to flow into the power input unit, and the phase detecting signal is outputted from the phase detector when the zero-crossing points of the AC voltage are detected. 
 
   
   
     12. The phase detecting device of  claim 11 , wherein the power switch comprises a first photocoupler. 
   
   
     13. The phase detecting device of  claim 12 , wherein the power switch receives a first predetermined DC voltage when the power switch is operating in the normal mode and supplies the first predetermined DC voltage to the first photocoupler when the power switch is operating in the normal mode; and
 wherein the power switch does not receive the first predetermined DC voltage when the power switch is operating in the standby mode and does not supply any voltage to the first photocoupler when the power switch is operating in the standby mode. 
 
   
   
     14. The phase detecting device of  claim 13 , wherein the power input unit comprises:
 a resistor circuit that divides the AC voltage and outputs a divided AC voltage; and 
 a bridge rectifier that rectifies the divided AC voltage and outputs a rectified AC voltage; and 
 wherein the phase detector detects the zero-crossing points of the AC voltage from the rectified AC voltage outputted from the bridge rectifier. 
 
   
   
     15. The phase detecting device of  claim 14 , wherein the phase detector comprises a second photocoupler connected to the bridge rectifier of the power input unit and the first photocoupler of the power switch. 
   
   
     16. The phase detecting device of  claim 15 , wherein the phase detector further comprises a 3-terminal element;
 wherein the 3-terminal element comprises:
 a first terminal that receives a second predetermined DC voltage and is connected to the second photocoupler, 
 a second terminal that receives the second predetermined DC voltage, and a third terminal that receives a ground voltage; and 
 
 wherein the second 3-terminal element
 outputs the ground voltage from the second terminal of the 3-terminal element as the phase detecting signal when the zero-crossing points of the AC voltage are detected and the power switch is operating in the normal mode, 
 outputs the second predetermined DC voltage from the second terminal of the 3-terminal element when the zero-crossing points of the AC voltage are not detected and the power switch is operating in the normal model, and 
 outputs the ground voltage from the second terminal of the second 3-terminal element when the power switch is operating in the standby mode. 
 
 
   
   
     17. The phase detecting device of  claim 16 , wherein the second predetermined DC voltage is different from the first predetermined DC voltage. 
   
   
     18. A phase control device that controls a phase of an AC power supplied to a controlled device, the phase control device comprising:
 a phase detecting device that receives an AC voltage, detects zero-crossing points of the AC voltage, outputs a phase detecting signal when the zero-crossing points of the AC voltage are detected, and selectively cuts off a flow of AC power into the phase detecting device in response to a mode control signal; and 
 a signal generator that generates a phase control signal to control the phase of the AC power supplied to the controlled device based on the phase detecting signal; 
 wherein the phase detecting device does not detect the zero-crossing points of the AC voltage when the phase detecting device cuts off the flow of the AC power into the phase detecting device in response to the mode control signal. 
 
   
   
     19. The phase control device of  claim 18 , wherein the phase detecting device comprises:
 a power input unit that receives the AC voltage; 
 a phase detector that detects the zero-crossing points of the AC voltage, and outputs the phase detecting signal when the zero-crossing points of the AC voltage are detected; and 
 a power switch that selectively cuts off the flow of the AC power into the power input unit in response to the mode control signal. 
 
   
   
     20. The phase control device of  claim 19 , wherein the power input unit comprises a full-wave rectifier that outputs a rectified AC voltage. 
   
   
     21. The phase control device of claim of  claim 20 , wherein the phase detector detects the zero-crossing points of the AC voltage from the rectified AC voltage outputted from the full-wave rectifier. 
   
   
     22. A phase control device that controls a phase of an AC power supplied to a controlled device, the phase control device comprising:
 a phase detecting device that receives an AC voltage, detects zero-crossing points of the AC voltage, outputs a phase detecting signal when the zero-crossing points of the AC voltage are detected, and selectively cuts off a flow of AC power into the phase detecting device in response to a mode control signal; and 
 a signal generator that generates a phase control signal to control the phase of the AC power supplied to the controlled device based on the phase detecting signal; 
 wherein the phase detecting device comprises:
 a power input unit that receives the AC voltage; 
 a phase detector that detects the zero-crossing points of the AC voltage, and outputs the phase detecting signal when the zero-crossing points of the AC voltage are detected; and 
 a power switch that selectively cuts off the flow of the AC power into the power input unit in response to the mode control signal; and 
 
 wherein the mode control signal comprises:
 a standby mode control signal that controls the power switch to operate in a standby mode in which a power consumption of the power input unit is reduced by cutting off the flow of the AC power into the power input unit, and the phase detecting signal is not outputted from the phase detector; and 
 a normal mode control signal that controls the power switch to operate in a normal mode in which the AC power flows into the power input unit, and the phase detecting signal is outputted from the phase detector when the zero-crossing points of the AC voltage are detected. 
 
 
   
   
     23. A phase detecting device comprising:
 a power input unit comprising a first terminal and a second terminal; 
 a phase detector comprising a first terminal and a second terminal, the first terminal of the phase detector being connected to the first terminal of the power input unit; and 
 a power switch comprising a first terminal and a second terminal, the first terminal of the power switch being connected to the second terminal of the phase detector, and the second terminal of the power switch being connected to the second terminal of the power input unit; 
 wherein the power input unit receives an AC voltage, generates an output voltage from the AC voltage, and outputs the output voltage across the first terminal of the power input unit and the second terminal of the power input unit; 
 wherein the power switch is operable in a normal mode in which the first terminal of the power switch is connected to the second terminal of the power switch, and a standby mode in which the first terminal of the power switch is disconnected from the second terminal of the power switch; 
 wherein when the power switch operates in the normal mode, the output voltage across the first terminal of the power input unit and the second terminal of the power input unit produces a current that flows out of the first terminal of the power input unit, through the phase detector via the first terminal of the phase detector and the second terminal of the phase detector, through the power switch via the first terminal of the power switch and the second terminal of the power switch, and into the second terminal of the power input unit, thereby causing the power input unit to consume power in the normal mode; 
 wherein when the power switch operates in the standby mode, no current flows out of the first terminal of the power input unit, through the phase detector via the first terminal of the phase detector and the second terminal of the phase detector, through the power switch via the first terminal of the power switch and the second terminal of the power switch, and into the second terminal of the power input unit, so that the power input unit does not consume power in the standby mode; 
 wherein when the power switch operates in the normal mode, the phase detector detects zero-crossing points of the AC voltage based on the current flowing through the phase detector, and outputs a phase detecting signal when the zero-crossing points of the AC voltage are detected; and 
 wherein when the power switch operates in the standby mode, the phase detector does not detect the zero-crossing points of the AC voltage, and does not output the phase detecting signal. 
 
   
   
     24. The phase detecting device of  claim 23 , wherein the power input unit comprises:
 a resistor circuit that divides the AC voltage and outputs a divided AC voltage; and 
 a full-wave rectifier that rectifies the divided AC voltage and outputs a rectified AC voltage as the output voltage across the first terminal of the power input unit and the second terminal of the power input unit. 
 
   
   
     25. The phase detecting device of  claim 23 , wherein the phase detector comprises a single switching circuit that detects zero-crossing points of both a positive polarity and a negative polarity of the AC voltage. 
   
   
     26. The phase detecting device of  claim 23 , wherein the power switch switches between the normal mode and the standby mode in response to a mode control signal. 
   
   
     27. The phase detecting device of  claim 26 , wherein the mode control signal comprises:
 a normal mode control signal that controls the power switch to operate in the normal mode; and 
 a standby mode control signal that controls the power switch to operate in the standby mode. 
 
   
   
     28. The phase detecting device of  claim 23 , wherein the power switch receives a predetermined voltage in the normal mode, thereby causing the power switch to operate in the normal mode; and
 wherein the power switch does not receive the predetermined voltage in the standby mode, thereby causing the power switch to operate in the standby mode. 
 
   
   
     29. The phase detecting device of  claim 28 , wherein the phase detector receives a predetermined voltage that enables the phase detector to operate;
 wherein the predetermined voltage received by the power switch during the normal mode is different from the predetermined voltage received by the phase detector. 
 
   
   
     30. A phase control device that controls a phase of an AC power supplied to a device, the phase control device comprising:
 the phase detecting device of  claim 23 ; and 
 a signal generator that generates a phase control signal to control the phase of the AC power supplied to the device based on the phase detecting signal. 
 
   
   
     31. A fuser control device that controls an AC power supplied to a fuser of an image forming apparatus, the fuser control device comprising:
 the phase detecting device of  claim 23 ; 
 a signal generator that generates a phase control signal to control a phase of the AC power supplied to the fuser based on the phase detecting signal; and 
 a temperature controller that controls a temperature of the fuser by controlling the phase of the AC power supplied to the fuser according to the phase control signal.